So you've got something releasing 1/40th the amount of energy of Thermite, slowly?
What am I missing?
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Taking the biggest peak, 22 W/g over 10 seconds, roughly triangular curve, so around 100 to 120 Joules per gram (Watts = Joules/Second)? Compare to say TNT at 4000 J/g? (and apparently regular thermite has similar energy content: http://www.nakka-rocketry.net/thermites.html)
So you've got something releasing 1/40th the amount of energy of Thermite, slowly?
What am I missing?
It doesn't explode. It's CLAY. Clay and red iron oxide will never explode. You're rediscovering the iron age, and you need to supply charcoal or coal, for you're smelting iron, and you're needing fuel.There was indeed aluminum. It wasn't elemental Al, true, but if it explodes, what difference does it make?
I'm sure any bronze age foundry man would disagree with you.It's unfounded and it's not science.
Like Harritt, then.Not only did they not replicate the study but they have also failed to achieve peer review and be in a position to publish their findings. Since then the people commissioning that study ( JREF ) have kept a very low profile on this subject.
It seems you're both wondering...And the remark from Jazzy - " Because they knew it wasn't reactive."- reminds me of NIST's classic line when asked why they didn't test for energetic material - " because we knew there was none there ". Science?
Taking the biggest peak, 22 W/g over 10 seconds, roughly triangular curve, so around 100 to 120 Joules per gram (Watts = Joules/Second)? Compare to say TNT at 4000 J/g? (and apparently regular thermite has similar energy content: http://www.nakka-rocketry.net/thermites.html)
So you've got something releasing 1/40th the amount of energy of Thermite, slowly?
What am I missing?
.There was indeed aluminum. It wasn't elemental Al, true, but if it explodes, what difference does it make?
It's unfounded and it's not science.
Can someone explain to me why the presence of Al in the red/grey chips is being challenged ?
Elemental aluminum. Aluminum the metal. They did not find any.
Sorry? I thought that you said that you had read the Harrit paper.
Page 1/25 of the pdf - Quote -
" The properties of these chips were analyzed using optical microscopy, scanning electron microscopy (SEM), X-ray energy
dispersive spectroscopy (XEDS), and differential scanning calorimetry (DSC). The red material contains grains approximately
100 nm across which are largely iron oxide, while aluminum is contained in tiny plate-like structures. Separation
of components using methyl ethyl ketone demonstrated that elemental aluminum is present. The iron oxide and aluminum
are intimately mixed in the red material."
Page 6/25 of the pdf - Quote -
"X-ray energy-dispersive spectroscopy (XEDS) analyses of both the red and gray layers from cross sections prepared from the four dust samples were performed and representative
spectra are shown in Figs. (6, 7). The four spectra in Fig. (6) indicate that the gray layers are consistently characterized
by high iron and oxygen content including a smaller amount of carbon. The chemical signatures found in the red layers
are also quite consistent (Fig. 7), each showing the presence
of aluminum (Al), silicon (Si), iron (Fe) and oxygen (O), and a significant carbon (C) peak as well."
This is quite apart from numerous charts showing the Al presence.
Why do you make the claim that they didn't find Al ?
What, so you are suggesting there was non-elemental non-nano particles of some compound of aluminum, in a reactive form?
That's not nano thermite then, is it.
Mick West said:How much energy did the "explosion" produce? What was the energy density?
That's a good question. I don't know exactly.
They did not actually FIND any elemental aluminum.
There's no strong evidence that elemental aluminum was present.
Do you know what elemental aluminum is? What's an example of non-elemental aluminum?
I didn't come here for a chemistry lesson, but my understanding is that elemental Al is almost never found because of its strong affinity to bind with oxygen and is far more usually found in silicates or oxides.
.... Elemental aluminum is found all over the place in buildings.
You know the difference between an element and a compound? Aluminum, the metal, is an element. Aluminum oxide is a compound. Finding aluminum in a substance via spectroscopy does not tell you if it's in elemental form or in compound form. Harrit infers there is some elemental aluminum from the peak ratios, but it's not really clear that this is correct, nor how evenly this applies to all the samples, nor if it's what you'd expect for "nanothermite"
Why is it not "clear that this is correct"? What does that mean? Why wouldn't it apply to all the samples? Because they didn't soak all the samples in MEK?
Again, I doubt your doubt.
What's going on there?
You have been considering the smelting of the iron oxide by the organic binder in the paint.
Approx 500 and 1500 degrees, temperature is an average measure of thermal vibrational energy, not its peak energy, and thus once in a while there will be sufficient energy for the reaction.At what temperature does that organic binder burn at? At what temperature does iron melt at ?
.I didn't come here for a chemistry lesson
.Approx 500 and 1500 degrees
Another bit of light bedtime reading here :- http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA320678
Click the PDF URL there.
Seems to me that the same 10C per min regime was applied to tests on various conventional explosives.( Page 17/36 of that pdf. ) The curves for many explosives tested appear to be similar to Harrit's. But no-one suggests that Semtex takes ten minutes to explode. Perhaps your puzzlement is a result of lack of understanding of this equipment.
Quite obviously that is the cause of my puzzlement.
[...]First of all I would have expected you to mention the scale
I think I mind if you liken a 'nano chip' to a wood-burning stove. Personally, what affronts me about that idea is the gross mismatch of scale and circumstances. At the scale of the wood stove, this would an oxide-to-metal scale. That's the way stoves normally are, aren't they? Please let's not get into stove technology...Secondly, when you say - "You have been considering the smelting of the iron oxide by the organic binder in the paint." - you are re-opening the old 'woodburner stove melting' debate.
[...]
But turning to your claim that organic material can consistently burn, in air, at a high enough temperature to melt iron in a steelframe building, on the grounds that it may be capable of doing that to an iron oxide particle in a crucible in a laboratory, is starting to appear like straw clutching.
[...]
It means it's not clear to me. I don't feel like I have enough information to determine it's correct.
I misunderstood the results as well. We both stand corrected. There should be no doubt as to the existence of elemental Al in the red matrix--again, unless you are saying the Harrit team is fabricating results or there is something wrong with their method....there also exist regions where the aluminum is concentrated but where the oxygen may not accompany it commensurately. To confirm and to quantify these observations, XEDS spectra (subsequent plots) were acquired from specific regions of high Si, Al and Fe concentrations.... Focusing the electron beam on a region rich in silicon, located in Fig. (15e), we find silicon and oxygen and very little else (Fig. 16). Evidently the solvent has disrupted the matrix holding the various particles, allowing some migration and separation of the components. This is a significant result for it means that the aluminum and silicon are not bound chemically....
The next XEDS spectrum (Fig. 17) was acquired from a region that showed a high concentration of aluminum. Using a conventional quantification routine, it was found that the aluminum significantly exceeded the oxygen present (approximately a 3:1 ratio). Thus, while some of the aluminum may be oxidized, there is insufficient oxygen present to account for all of the aluminum; some of the aluminum must therefore exist in elemental form in the red material.
I'm not sure what you mean there. Perhaps you could quote the relevant sections?It's not dust if the piece they found evenly distributed Al in the matrix was soaked in MEK for hours.
I'm not sure what you mean there. Perhaps you could quote the relevant sections?
Mick, are you disagreeing with a paper which you have not read?